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> The answer is that birth rate needs to decline and the human population needs to level off and then also decline to sustainable levels. I agree that's an ans

> The answer is that birth rate needs to decline and the human population needs to level off and then also decline to sustainable levels. I agree that's an answer, but is it the answer? It seems like reproduction rates in wealthy countries trend closer towards replacement levels, so perhaps you "just" need to get everybody's standard of living up to western levels to take population growth out of the equation. Then you're left with supporting roughly our current population level which seems... entirely feasible? Between existing but underutilized techniques like fission, renewables, smarter land use and management for agriculture (read: focus on producing more efficient crops and less on the intensive stuff like cows), retrofitting buildings with better insulation, and building out more efficient transit, it seems like we could get pretty close with current levels of technology. Nevermind the developments we continue to make. Fusion power would immediately solve a lot of problems.

titzer 3y ago
> Then you're left with supporting roughly our current population level which seems... entirely feasible? That doesn't match data I've seen. For example, even the Wikipedia article on carrying capacity (https://en.wikipedia.org/wiki/Carrying_capacity https://en.wikipedia.org/wiki/Carrying_capacity), second paragraph, states there are a number of lines of scientific evidence that we are already over capacity of Earth today. One project (https://en.wikipedia.org/wiki/Earth_Overshoot_Day https://en.wikipedia.org/wiki/Earth_Overshoot_Day) does pretty intense data analysis to quantify how far we are over that capacity. The summary is, yes, we are definitely in overshoot, and all economic development to raise standard of living is making it worse. But it's even worse than that. We aren't just exceeding the carrying capacity, it is diminishing as we reduce biodiversity and biomass through land use (read: obliterating wildlife and forests), overfishing, and over-industrialization of agriculture, which kills healthy soils. > Between existing but underutilized techniques like fission, renewables, smarter land use and management for agriculture It's not just about producing more energy. We are consuming everything too much, from biomass to raw materials, even fresh water. > Fusion power would immediately solve a lot of problems. It might reduce CO2 consumption but ironically it will increase per capita energy consumption, which encourages even more environmental destruction by making everything cheaper to build and buy. So more land use and more consumption.
- williamcotton 3y ago
  Malthus had plenty of scientific evidence as well! What he didn’t have was fertilizer and tractors.
  - dbspin 3y ago
    Fertilizer and tractors both contributed enormously to devastaing the biodiversity of the planet. The question is not whether we can sustain a larger population, but whether we can sustain a population as large as currently exists - while maintaining any semblance of a natural world. Over a long enough time line both questions almost certainly do in fact merge. But it's equally possible to conceive of a medium term future with nature utterly devastated and humanity clinging on in increasingly baroque ways to a dying rock.
tuatoru 3y ago
> It seems like reproduction rates in wealthy countries trend closer towards replacement levels... That seems unlikely, given that total fertility in wealthy countries is well below "replacement" (2.1 children per woman). Reproduction rate, number of daughters per woman, could only be approaching replacement if the sex ratio is massively skewed in favour of girls. 1. UN chart of TFR for "more developed regions": https://population.un.org/wpp/Graphs/Probabilistic/FERT/TOT/901 https://population.un.org/wpp/Graphs/Probabilistic/FERT/TOT/... Observe the assumed but never yet seen floor to fertility rate.

titzer 3y ago

> Then you're left with supporting roughly our current population level which seems... entirely feasible? That doesn't match data I've seen. For example, even the Wikipedia article on carrying capacity (https://en.wikipedia.org/wiki/Carrying_capacity https://en.wikipedia.org/wiki/Carrying_capacity), second paragraph, states there are a number of lines of scientific evidence that we are already over capacity of Earth today. One project (https://en.wikipedia.org/wiki/Earth_Overshoot_Day https://en.wikipedia.org/wiki/Earth_Overshoot_Day) does pretty intense data analysis to quantify how far we are over that capacity. The summary is, yes, we are definitely in overshoot, and all economic development to raise standard of living is making it worse. But it's even worse than that. We aren't just exceeding the carrying capacity, it is diminishing as we reduce biodiversity and biomass through land use (read: obliterating wildlife and forests), overfishing, and over-industrialization of agriculture, which kills healthy soils. > Between existing but underutilized techniques like fission, renewables, smarter land use and management for agriculture It's not just about producing more energy. We are consuming everything too much, from biomass to raw materials, even fresh water. > Fusion power would immediately solve a lot of problems. It might reduce CO2 consumption but ironically it will increase per capita energy consumption, which encourages even more environmental destruction by making everything cheaper to build and buy. So more land use and more consumption.

williamcotton 3y ago
Malthus had plenty of scientific evidence as well! What he didn’t have was fertilizer and tractors.
- dbspin 3y ago
  Fertilizer and tractors both contributed enormously to devastaing the biodiversity of the planet. The question is not whether we can sustain a larger population, but whether we can sustain a population as large as currently exists - while maintaining any semblance of a natural world. Over a long enough time line both questions almost certainly do in fact merge. But it's equally possible to conceive of a medium term future with nature utterly devastated and humanity clinging on in increasingly baroque ways to a dying rock.

tuatoru 3y ago

> It seems like reproduction rates in wealthy countries trend closer towards replacement levels... That seems unlikely, given that total fertility in wealthy countries is well below "replacement" (2.1 children per woman). Reproduction rate, number of daughters per woman, could only be approaching replacement if the sex ratio is massively skewed in favour of girls. 1. UN chart of TFR for "more developed regions": https://population.un.org/wpp/Graphs/Probabilistic/FERT/TOT/901 https://population.un.org/wpp/Graphs/Probabilistic/FERT/TOT/... Observe the assumed but never yet seen floor to fertility rate.